where \(S_3\)  is the three dimensional Euclidean action.
From this equation, the probability of existing the false vacuum is given by [1]}
\(F(t) = \exp \left[ -\frac{4\pi }{3}\int ^t_{t_i} dt^{\prime } \Gamma (t^{\prime }) a^3(t) r^3(t,t^{\prime }) \right],\) 
